Heretofore, as will be described in greater detail hereinafter, in the cathodic protection of metal conduit in a wellbore, an anode has been set in the earth relatively near to the wellbore and an electrical circuit established between the anode and wellbore, part of which circuit was the earth connection between the anode and the wellbore. The anode was normally set into the earth relatively close to the wellbore.
When a wellbore is drilled in northern climates wherein permafrost (permanently frozen earth) occurs to a finite distance below the earth's surface, a problem arises in cathodic protection because the normal resistivity of permafrost is substantially higher than the normal resistivity of unfrozen earth.
This invention is directed towards a method for cathodic protection of metal conduits in wellbores in permafrost, the substantially higher resistivity of the permafrost notwithstanding.